A device disclosed in Japanese Published Unexamined Patent Application No. 2002-33153 is conventionally known as an electrical connecting device that has a male connector component, which supports a pair of connecting terminals, and a cover element fitted to the male connector component and that is connected to a female connector component supporting a pair of to-be-connected terminals. The electrical connecting device disclosed in this publication (No. 2002-33153) is a plug connector that is connected to a socket connector so as to realize an ignition circuit of a detonator of an air bag gas generator for vehicles. This electrical connecting device is made up of a connector housing (i.e., male connector component), a connector cover (i.e., cover element), and a pair of electric contacts (i.e., a pair of connecting terminals). The electrical connecting device is designed so that the connector cover is fitted to the connector housing so as to form a unit as a plug connector in a state in which the electric contact is held. The plug connector formed as a unit is fittably inserted into a socket cavity (opening) formed in the socket connector (female connector component), and is electrically and mechanically connected to the socket connector. At this time, a protruding rib provided at an arm extended from the connector housing is engaged with an engagement groove of the socket cavity, so that the socket connector and the plug connector are mechanically locked together.
However, in the electrical connecting device disclosed in Japanese Published Unexamined Patent Application No. 2002-33153, the mechanical locking between the female connector component (socket connector) and the plug connector is realized by the engagement between the protruding rib formed on the male connector component (connector housing) and the engagement groove formed in the opening (socket cavity) of the female connector component. Therefore, a conventional problem resides in the fact that when an external force acts on the electrical connecting device connected to the female connector component (e.g., when a tensile force arises in a lead wire connected to the connecting terminal, or when a blast generated by the inflation of an air bag acts thereon), the cover element (connector cover) is easily disengaged even if the male connector component is locked onto the female connector component.